太陽能輻射計

I was skeptical at first, but within seconds of placing it in direct sunlight the vanes started spinning steadily. It’s a fascinating demonstration of heat energy in action.

Set it near a sunny window and the four blades pick up speed almost immediately, the black and white panels turning a full rotation within a minute. It’s a simple way to watch heat and light do their thing, and it’s been a conversation starter on my desk ever since.

The first time I held my palm close to the glass, the vanes started turning before I even switched on a light—pure heat, no sun needed. It’s a great conversation piece for the desk, and watching the blades spin faster when a warm laptop exhaust hits it never gets old.